In general, a dispensing device is used for converting a large amount of liquid, which is used in fine chemicals industry, into minute particles and precisely coating a specific portion of a target product, for instance, in order to join the target product or process the surface of the target product with a specific coating liquid. Such a coating liquid is injected through a dispensing gun, namely, through a nozzle of a jet valve disposed on the dispensing gun, so as to precisely join or process materials, for instance, in the semiconductor manufacturing process.
In order to enhance the degree of precision, an outlet of the nozzle to inject the coating liquid is formed finely, and hence, it is very important to control injection pressure, time, speed, range, amount, and others of the coating liquid injected through the nozzle instantly.
The jet valve is conveyed together with a robot arm in a position selectable manner from a conveying device or is controlled by a program set to be moved in horizontal and vertical directions according to the position movement of a transfer in order to inject and coat the coating liquid to the specific portion so as to process the target product. In a state where coating work from the nozzle is finished, the coating liquid remaining on the nozzle is cleaned and washed off by the air blowing method.
However, because the coating liquid is minutely accumulated on an end portion of the nozzle from which the coating liquid is injected, it influences on the dispensing accuracy of the coating liquid. Moreover, such a problem gradually has an influence on the next injection of the coating liquid, and hence, causes a faulty process of the target product.
Furthermore, there is an inconvenience to reset air consumption according to ingredients of the coating liquid, and it causes difficulty in performance recovery of the jet valve because of accumulation of foreign matters on the nozzle due to a change in pressure.
In order to overcome the above problem, the inventor of the present invention has Korean Patent No. 10-996557 entitled “nozzle cleaning apparatus of a dispensing jet valve”.
In Korean Patent No. 10-996557, as shown in FIG. 1, the nozzle cleaning apparatus 100 of the dispensing jet valve includes: a roll brush (120) for cleaning a nozzle 2 of the lower part of a jet valve 1 which is moved from a dispensing device and disposed for injecting a coating liquid to join and process a specific portion of a target product; and driving means 130 for rotating the roll brush 120 in forward and backward directions. The nozzle cleaning device 100 further includes: a mounting block 110 having a first space part 111 opened at the top portion, a second space part 112 disposed at the rear of the first space part 111 and opened at the top portion and both sides, and a connection part 113 disposed at the lower part of the front and having a joining hole 113a to which a fastening member (S) is fixed from the dispensing device, the roll brush 120 being mounted inside the first space part 111 of the mounting block 110, the driving means 130 being mounted in the second space part 112 of the mounting block 110 and connected to the roll brush 120 via a rotational connection shaft 131 penetrating the first space part 111 from the second space part 111, such that the driving means 130 rotatably drives the rotational connection shaft 131 by air pressure so as to rotate the roll brush 120 in forward and backward directions; a driving pressure controller 150 connected with air supply lines (P) to control a driving pressure by air supply; a main controller 160 electrically connected with the driving pressure controller 150 so as to control a driving time setting and a power supply of the driving pressure controller 150; and a pollution preventing cover 140 disposed on the top of the first space part 111 and having an open middle portion, which is smaller than an area of the opened top portion of the first space part 111, and, to which the bottom portion of the jet valve 1 is guided, such that foreign matters are not scattered to the outside when the nozzle 2 of the jet valve 1 is cleaned.
That is, the nozzle 2 cleans the coating liquid stained on the nozzle using the rotational roll brush 120. However, because the residue of the coating liquid scattered through the roll brush is, in fact, minutely stained on the nozzle again, the roll brush needs a sufficient rotation period of time. Accordingly, the nozzle cleaning device of the dispensing jet valve has a disadvantage in that it takes a long period of time to clean and wash off the coating liquid through the dispensing device.